Chemically defined amino acids and their derivatives such as peptides which contain no animal-derived components are now widely considered to be the preferred choice for use as components in the field of cell culture media for biopharmaceuticals and vaccines.

Compared to animal-sourced materials such as fetal bovine serum and undefined protein hydrolysates, they eliminate the risk of critical contaminants via sources such as BSE, mycoplasma or viruses. Of equal importance, their well-defined and highly pure nature minimize the risk of batch composition variations for more consistent and reliable media performance. Increasing regulatory scrutiny has also increased the need for precisely detailed insights into the exact media composition.

However, biopharmaceutical manufacturing processes using Chinese Hamster Ovary (CHO) cell lines or other mammalian cells have become highly specialized over the last two decades. This growing need for intensified and high-performing biopharmaceutical processes, especially where highly concentrated feeds or perfusion media are required, has prompted the need to move beyond the traditional use of protein hydrolysates. In particular, it is now common for the biopharma industry to require the use of peptides and performance boosters that are highly stable and soluble in neutral pH.

With the right selection of chemically defined peptides, keto acids, special amino acids or other derivatives at hand, biopharmaceutical companies can realize substantial process improvements to help prolong longevity, solubilize critical constituents and better manage the concentration of essential nutrients. In particular, such ingredients can:

• Optimize Consistency: The use of precisely defined components under easily reproducible conditions, instead of poorly or non-defined complex mixtures, removes a key source of batch-to-batch variation.
• Reduce Risk: The use of well-defined GMP ingredients with extensive data packages and quality documentation can enable the delivery of non-soluble amino acids without any requirement to use caustic feeds, eliminating the risk of losing high-value batches due to accidental overdosing.
• Boost Productivity: Even small amounts of performance boosters can improve titer, shorten development times and boost productivity, which can be highly impactful given the high costs of manufacturing each batch for many biologics today.

By combining an essential lead amino acid with another that compensates for traditional limitations such as poor solubility or instability, peptides can serve as an attractive choice to fully or partially substitute the traditional form in basal media or feeds. There are four main categories where peptides and performance boosters can provide the greatest value for biopharmaceutical companies.

• Glutamine Peptides: The amino acid L-glutamine is well known to exhibit limited chemical stability in water or equivalent solutions. This tendency to easily degrade can adversely impact overall cell culture performance through elevated levels of ammonia, glutamic acid or pyroglutamate. Substitution of L-glutamine with stabilized peptide forms can help to prevent decomposition that can otherwise release free ammonia into media or feeds, thus affecting cell viability and protein quality. Flexibility in media design can be optimized when platforms are utilized that offer a choice between alanine and glycine peptides.
• Tyrosine and Cystine Peptides: L-tyrosine and L-cystine - exhibit poor solubility in water and media, and thus impose limitations to media and process optimization. Because they often cannot be prepared at the desired concentration at a neutral pH, the use of extreme pH values is often required resulting in significant increases in solubility. Consequences can include the need to separate feed tanks, cumbersome processes for pH control, the use of excess salt, and the risk of precipitation in the bioreactor. Substitution of L-tyrosine and L-cystine with peptides can help increase solubility at neutral pH by up to 1000 times. Because these peptides can be efficiently taken up and metabolized by the cell, full replacement is also possible.
• Additives: Other additives to amino acids, such as the keto acid α-ketoglutaric acid (AKG), can further help to boost performance and protect primary or cell cells against oxidative stress or ageing.

All peptides marketed by a supplier for use within these cell culture segments should be available from small to commercial scale volumes to match specific batch requirements.

As one of the world’s leading specialty chemical companies with decades of expertise in high purity chemically defined amino acids and cell culture ingredients, Evonik is ready to serve as a strong, stable and reliable supply partner and solutions provider to biopharma companies. Teams of experts are available around the world with extensive chemistry, biotech, purification and formulation knowhow. To request an initial consultation or request a free sample kit of peptides to conduct initial feasibility studies, contact Evonik via healthcare@evonik.com.